Constrained plasma shape control in ITER

Abstract

This paper presents an application of a novel constrained control methodology known as Command Governor (CG) to the shape control of plasmas in thermonuclear fusion reactors. The CG strategy is based on predictive control ideas and consists in modifying, whenever necessary, the reference signal supplied to a primal internal loop controlling the plasma distance from the internal walls of the tokamak, taking into account constraints due to voltages saturations on the converters, currents limitations in the active coils for magnetic confinement, force limits on the mechanical structures, minimum clearance between the plasma and the vacuum chamber wall, maximum induced forces on coils. The reference signal modification is accomplished through an on-line optimization procedure which embodies plasma model forecasts computed along a finite time virtual receding horizon. A numerical example with about a hundred of constraints, is developed with reference to ITER.